Rotary pump



V. R. EBSARY April 24, 1951 ROTARY PUMP 3 Sheets-Sheet l Filed Aug. 9,1945 April 24, 1951 v. R. EBsARY 2,550,540

ROTARY PUMP Filed Aug. 9, 1945 5 Sheets-Sheet 2 April 24, 195jh v. R.EBsARY 2,550,540

ROTARY PUMP Filed Aug. 9, 1945 3 Sheets-Sheet 3 H04 #Pf/57:?MzzmQVa/"dfg @MQW J #www Patented Apr. 24, r1951 weer OFFICE ROTARY PUMPVivian Richard Ebsary, Darlinghurst, nearl Sydney, New South Wales,Australia Application August 9, 1945, Serial No. 609,801

.This invention has' been devised to provide a rotary pump primarily foruse as an exhausting f... pump, that is for creating a vacuum. The pumpis particularly useful for creating a high degree of vacuum, forexample, up to the order of three microns in a single stage, as isfrequently required in laboratory work and in certain industrialundertakings. But the characteristic features which make the pump seuseful for the aforesaid` purpose make it economically adaptable as amedium vacuum pump for general use, as for example, in milking machinesand or as a medium pressure compression pump.

1 In Australia August 1o, 1944 f' 7 claims. (o1. 10s- 121) pump isdesigned. Suction ports are formed in the stator on one side of the vaneand discharge ports with or without delivery valves therein are formedon the other side of the vane. Conduits lead from the suction anddelivery ports respectively throughthe stator to inlets and outlets atthe closed end of the cylinder.

The rotor is an eccentric sleeve which is a working fit in the cylinderand which at its major One characteristic feature of the invention isvthe construction which provides automatic com-'- pensation for linearwear and or expansion or contraction of the rotor and the stator. Theconstruction permits of the working clearances being so nely adjustedthat working losses due to linear clearances are substantially obviated.

Another feature of the invention is the construction .wherein the rotoris supported lindependently of driving means, therefore -efciency lossesdue to rotor displacement by weight of the driving means is obviated.

A still further feature of' the invention is the construction whichprovides yfor an oil filmin the pump chamber between the faces of therotor andthe stationary parts in contact therewith whereby wear due tofrictional contact is reduced to a minimum.

Basically the pump of this invention consists of a sleeve rotor havingan eccentric bore and means to close the ends of said bore; a stator inthe rotor having a sliding vane in contact with 1 the wall of saideccentric bore and having a suction port on one side of said slidingvane and discharge port on the other side of said vane;

conduits from said suction and discharge ports projecting through thesaid stator; and means to rotate the sleeve rotor concentrically about"said stator. It is within the basic principle set out in the precedingparagraph to employ a sleeve rotor having a concentric bore and toprovide meansA to rotate said rotor eccentrically about the stator.Alternatively means may be incorporated to cause such a sleeve rotor totravel in an eccentric path around the stator and in continuous contacttherewith without necessarily rotating the sleeve.

rotor. 4

`In one embodiment of the invention there Vis la cylinder open at oneend which constitutes a housing and a bearing for the rotor, and ahousing anda support for the stator; s The stator is an axial bosshoused in the cylinder and rigidly mounted on the closed end thereof.There is a longitudinal slotin the wall of the stator and a vane in thisslot is thrustradially outwardly by means appropriate for the workiorwhich the is a clearance nt in the end of the cylinder.

thickness. is a working t between the cylinder wall and the stator.- Anend cover on the rotor A helical spring and/or other i'luid means holdsthe rotor in position. This spring or other means is required, in avacuum pump, only during the starting operation, for when a negativepressure is created in the pump the rotor is retained in positionthereby. When the pump is designed as a pressure pump means are providedto act against the end cover of the rotor to compensate forthe outwardthrust of the rotor due to the ypressure created. An oil ilmV isprovided bee Vtween the rotor and the end cover of the cylinder and oilfrom this lm lubricates theV working parts. The rotor may Ice4 actuatedby a drive to its periphery through the cylinder or by a coupling to theend cover.

Ihe embodiment' of the invention described'in general terms above isillustrated in greater detail in the annexed drawings whereinFigl is aperspective view partly in section of a pump with accessory equipmentdesigned to create a high degree of vacuum; Fig. 2 is a longitudinalcentral sectional elevation of the same pump and accessory equipment;Fig. 3 is a section on line 3-3 of Fig. 2; Fig. 4 is a section on lined-4 of Fig. 3.

Referring to Figs. 1 to 4 the pump is totally enclosed in a casing I0which has feet I Ifor i ailixture to a base and an end cover I2 held inplace by set bolts I3. The casing and the .cover `are constructed to beliquid tight atleast to a position above the pump. The cover I2.constiVtues a base support for the pump.

The pump stator cylinder I4 has an end cover I5; it is open at the otherend. Brackets I6 on the end `cover I5 fit into lugs I'I on the base I2and they are rigidly held thereon by set bolts I8. Header boxes Ill-20are formed on or mounted on the end cover I5 and lugs 2| providebearings for a pvot pin 22 for a lever which will be referred to later.

In the cylinder I4 is the stator which consists of an axial boss 23aixed to the end cover I5 by set bolts 24 and aligning dowels 25.Alternatively the stator boss 23 may be formed as an integral part ofthe end cover I5. This stator 23 projects to near the end of thecylinder I4 (see Fig. 2) it has a central cavity 26 in conjunction witha .longitudinal slot 21 which` latter houses sliding vane 2B. Lever 29mounted on the pivot pin 22 projects into the cavity 26 and bears uponthe sliding vane 28 thrusting it outwardly by the action of the spring30 anchored to said lever and to stud .3l on the cylinder end cover l5.

It will be appreciated that other means as well known in the art may beemployed to thrust the sliding vane 28 outwardly in the operation of thepump. For example the cavity 26 may be formed as a conduit fol hydraulicliquid with a column for such liquid projecting from between the headerboxes l9-20. The back of the vane 28 or plungers formed thereon wouldtake the weight of the column of liquid and if necessary such weight maybe increased by a spring loaded plunger in the column to assist inhydraulic balance.

A number of suction ports 32--say ve-are formed in the stator23; theyare in longitudinal alignment on one side of the sliding vane 28 andthey provide communication from the periphery of the stator to conduit33 also formed in the stator which leads to the header box I9 and inletpipe 34 connected to oil trap 35 in the casing I0. The function of thisoil trap will be described later.

A number of discharge ports 36-say ve--are also formed in the stator 23.These ports are in longitudinal alignment on the opposite side of thesliding vane 28 to the suction ports 32. They have non-return valves 31(such as ball valves) therein and means (not shown) are provided tolimit the travel of the valves. These valves are on valve seats adjacentthe periphery of the stator and are so positioned to avoid dead pocketsin the pump. The discharge ports 36 communicate with conduit 38 alsoformed in the stator which leads to header box 20 and outlet pipe 39.This outlet pipe 39 terminates above the pump and there isY an exhaustoutlet in the top of the casing, indicated at 40.

The pump rotor 4I is an eccentric sleeve which is conveniently made as acasting and cored about its major part as indicated at 42 for balanceand lightness in construction. The outer Wall of the rotor is machinedtrulyto constitute a working fit in the cylinder I4. Thisy wall is thebearing surface of' the rotor and it may be grooved to providelubrication ducts or the internal Wall of the cylindery can be groovedfor suchrpurpose. Lubrication ports may bey made in thel wall of thecylinder ory lubricant may be admitted Afrom the end of the cylinder. YY

The internal wall of the rotor is also machined truly, `eccentric, tothe outer wall, and at the major center, that is, the point of'ygreatest distance betweenl thel inner and outer walls, an arcuate grooveconcentric tothe said' outer Wallindicatedat 43-is-madein the wall, theradius of the groove being the same as the radius of the stator 23 plusa minute Working clearance. The area adjacent this 'grooye` constitutesa wedge cavity'for a lubricant seal between the stator and the rotorand' the lubricant is carried thereto' by the internal wall of therotor.

Rotor end'` cover 44i is a clearance fit in the cylinder` I4; it isailxed tothe rotorl by set' screws 45. On its outer face, this rotoriend cover has a boss 45 with a friction washer 48a' thereon; andahelical-f spring "mounted on said' boss and` on boss 481 onthe end`wall of the casing' I0; holds the coverf and the rotor in= position;

There is` a circular recess lillJ inthe periphery ofL therotor with aringcgear'wheeli' 5U formed or mcuntedf` thereon@Y This` ring" gearwheel is in mesh 'with pinion 5I= on shaft 521 inbearings' A53" on thetop of the cylinder `l4. The cylinder is slotted to permit the gears toengage. The shaft 52 projects through the cover I2 of the casing l0 andit is connected to a power unit (not shown) through an overload slippingclutch 54. There may be a gland in the cover l2 to prevent leakagearound the shaft.

The pump is submerged in oil and the oil reaches to the level of thebase of the oil trap vessel 35. Float 55 is attached to a rigid floatarm 55a which is pivoted at 55h so that the float may ride at all timeson the oil level in housing lll. f Oil trap 35 is provided with anoutlet valve assembly 56 having a valve body 56a and a valve seat 55h,the valve body 56a being actuated by and in registry with float arm 55a.The oil trap vessel 35 has an inlet pipe 51. leading through the casingl0 and this pipe may have a liquid seal vessel such as 58 thereonadapted to seal the end of a pipe connecting the pipe 5l' With a suctionline. The oil trap vessel 35 with its Valve and Voat is a safety deviceadapted to function when the pump is stationary. If when the pump isstationary the suction line is 1eft under a reduced pressure oil may bedrawn from the casing l0 through the pump and into the suction line. Ifallowed to be drawn into apparatus connected to the Vsuction line thisoil may cause damage thereto. This is prevented by rst trapping the oilin the oil trap vessel 35 and as the oil level in the casing l0 dropsthe outlet valve 56a opens by operation of the iioat 55 and float arm55a, breaks the vacuum in the suction line and allows the oil in the oiltrap vessel 35 to ow back to the casing I8.

I claim:

1. A rotary pump comprising a cylinder having a cover at one end and theother end being open, said cylinder constituting a housing and a bearingfor a rotor, and a housing and a support for a stator; an axial bossconstituting the stator affixed to the cover of said cylinder;` a sleeverotor having an eccentric bore housed in said cylinder; a cover on theend of said sleeve rotor remote from the cylinder cover', said sleeverotor cover being a clearance nt in said cylinder; `means to rotate saidsleeve rotor concentrically in said cylinder; a. sliding vane in saidstator in contact with the eccentric boreo'f said rotor; a suction portin said stator on one side ofsaid sliding Vane; a discharge port in saidstator on the other side of said sliding vane; and conduits from saidsuction and Ydischarge ports projecting through said stator and saidcylinder.y

2.. A rotary pump comprising a cylinder having a. cover at. one end andthe other end. being open, said cylinder constituting a housing andv abearing for a. rotor, and ar housing and. a support for a. stator; anaxial boss constitutingA the stator aflixed to the cover oit saidcylinder; avsleevev rotor having an eccentric bore housed. inA saidcylinder; av cover ort the end` of.-saidl sleeveA rotor remote from thecylinder cover,. said sleeve rotor cover being a clearance fit in saidcylinderymeans to rotate said sleeve rotor concentricall'yv in. saidcylinder; a; sliding v'ane in saidY stator; means to hold said slidingvane in contactwi-th the eccentric bore o'f said rotor; a suction portin said statorV on one side oi" said sliding vane; and a discharge portin said stator on the' other. side of said sliding vane;` and conduitsfrom said suction and discharge ports' projecting through said statorand said cylinder.

3. A rotary pump comprising acylin'der having a' cover 011 One' end.andthe otherV end open,

said cylinder constituting a housing and a bearing for a rotor, and ahousing and a support for` a stator; an axial boss constituting thestator aflixed to the cover of said cylinder; a sleeve rotor having aneccentric bore housed in said cylinder; a cover on the end of saidsleeve rotor remote from the cylinder cover, said sleeve rotor coverbeing a clearance fit in said cylinder; means to rotate said sleeverotor concentrically in said cylinder the internal wall of said rotorhaving at the point of greatest difference between vthe inner and outerwalls an arcuate groove conand discharge ports projecting through saidstator and said cylinder.

4..,A rotaryl pump comprising a cylinder hav- Y ing a cover at one endand the other end being open, said cylinder constituting a housing and abearing for a rotor, and a housing and a support for a stator; an axialbossconstituting the stator affixed to the cover of said cylinder;l asleeve rotor having an eccentric bore housed in said cylinder; a coveron the end of said sleeve rotor remotefrom the cylinder cover, saidsleeve rotor cover beingA a clearance lt in said cylinder;

`means to rotate said sleeve rotor concentrically in said cylinder; asliding vane in said stator; means to hold said sliding vane in contactwith thev eccentric bore of said rotor; a suction port in said stator onone side, of said sliding vane; a discharge port inv said stator on theother side of Vsaid sliding vane; conduits from said suction anddischarge ports projecting through said stator and said cylinder; alliquid lled casing for said cylinder; a liquid trap vessel in saidcasing having an inlet pipe connected to the top thereof; an outlet pipefrom the bottom of said vessel connected to the conduit from saidsuction port; and means including a valve associated with the ing acover at one end and the other end being open, said cylinderconstituting a housing and a bearing for a rotor, and a housing and asupport for a stator; an axial boss constituting the stator aiixed tothe cover of said cylinder; a sleeve rotor having an eccentric borehoused in said cylinder; a cover on the end of said sleeve rotor remotefrom the cylinder cover, said sleeve rotor cover being a clearance fitin said cylinder; means to rotate said sleeve rotor concentrically insaid cylinder, said stator having a slot in the periphery thereof and aninternal cavity with y an opening at one end thereof; a vane slidable in`bottom of said trap vessel for draining liquid fromsaid trap vesselinto said casing.

5. A rotary pump comprising a cylinder havl ing a cover at one end andthe other end being said cylinder constituting a housing and a bearingfor a rotor, and a housing and a support for a stator; an axial bossconstituting the stator aiixed to the cover of said cylinder; a sleeverotor having an eccentric bore housed in said cylinder; a cover on theend of said sleeve rotor remote from the Acylinder cover, said sleeverotor cover Open,

ybeing a clearance fit in said cylinder; means to rotate said sleeverotor concentrically in said cylinder, said means -consisting of a ringgear on the periphery of said sleeve rotor; a pinion gear engaging saidring gear; a shaft for said pinion gear; means to actuate said shaft; asliding vane in said stator; means to hold said sliding vane in contactwith the eccentric bore of said rotor; a suction port in said stator onone side of said sliding vane; a discharge port in said stator on theother side of said sliding vane; and conduits from said suction anddischarge ports projecting through said stator and said cylinder.

6. A rotary pump comprising a cylinder bavsaid slot; a lever pivotallymounted outside said stator, projecting into said cavity and bearing onsaid vane; a spring adapted to apply pressure to said lever; a suctionport in said stator on one side of said sliding vane; a discharge portin said stator on the other side of said sliding vane; and conduits fromsaid suction and discharge ports projecting through said stator and saidcylinder.

7. A rotary pump comprising a cylinder having a cover at one end and theother end being open, said cylinder constituting a housing and a bearingfor a rotor, and a housing and a support for a stator; an axial bossconstituting the stator Vaflixed to the cover of said cylinder; a sleeverotor having an eccentric bore housed in said cylinder; a cover on theend thereof remote from the cylinder cover, said sleeve cover being aclearance fit in said cylinder; means to rotate said sleeve rotorconcentrically in said cylinder; a sliding vane in said stator; means tohold said sliding vane in contact with the eccentric bore of said rotor;a suction port in said stator on one side of said sliding vane; adischarge port in said stator on the other side of said sliding vane;conduits from said suciton and discharge ports projecting through saidstator and said cylinder; a liquid lled casing for said cylinder; aliquid trap vessel in said casing having an inlet pipe connected to thetop thereof; and outlet pipe from the bottoni of said vessel connectedto the conduit from said suction port; a valve in the bottom of saidtrap vessel; a float adapted to rest on the surface of the liquid insaid casing; and means operatively associated with said float and saidvalveV for opening and closing the valve upon predetermined variation ofthe liquid level in the casing.

VIVIAN RICHARD EBSARY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS France Feb. 9, 1931

